Long-term effect of high dose omega-3 fatty acid supplementation for secondary prevention of cardiovascular outcomes: A meta-analysis of randomized, double blind, placebo controlled trials

Background: Although omega-3 fatty acids have well documented properties which would reduce the cardiovascular (CV) disease risk, the evidence from randomized controlled trials (RCTs) remains inconclusive. We performed a meta-analysis of the available RCTs for investigating the CV preventive effect of administrating at least 1 gram/day, and for at least 1 year, omega-3 fatty acid supplements to patients with existing CV disease. Methods: RCTs published up to March 2013 were searched from PubMed, EMBASE, and the Cochrane Library. Two of us independently reviewed and selected eligible trials. Results: Of 360 articles retrieved, 11 randomized, double-blind, placebo controlled trials fulfilling inclusion criteria, overall involving 15,348 patients with a history of CV disease, were considered in the final analyses. No statistically significant association was observed for all-cause mortality (RR, 0.89; 95% CI, 0.78 to 1.02) and stroke (RR, 1.31; 95% CI, 0.90 to 1.90). Conversely, statistically significant protective effects were observed for cardiac death (RR, 0.68; 95% CI, 0.56 to 0.83), sudden death (RR, 0.67; 95% CI, 0.52 to 0.87), and myocardial infarction (RR, 0.75; 95% CI, 0.63 to 0.88). Conclusion: Overall, our results supply evidence that long-term effect of high dose omega-3 fatty acid supplementation may be beneficial for the onset of cardiac death, sudden death and myocardial infarction among patients with a history of cardiovascular disease.